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(a) East-west, B-B 0 ; Early Mesozoic normal faults are bolder than younger faults and (b) northeast-southwest, C to C 0 cross sections of the Rongma area. See Foldout 2 for lines of section and unit abbreviations. Abbreviations are: gsch, greenschist-facies melange; bsch, blueschist-facies melange; C1, Carboniferous quartzite-bearing siliciclastic rocks; C2, Carboniferous limestone-bearing strata; P1, Permian turbiditic sandstone; P2, Permian limestone; P3, Permian mafic volcanic rocks and conglomerates; P4, Permian limestone and sandstone; Ts2, Tertiary nonmarine strata; N-Q, NeogeneQuaternary conglomerate; Qal, Quaternary alluvium.
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1] A >500-km-long east-west trending metamorphic belt in the Qiangtang terrane of central Tibet consists of tectonic melange that occurs in the footwalls of Late Triassic – Early Jurassic domal low-angle normal faults. The melange is comprised of a strongly deformed matrix of metasedimentary and mafic schists that encloses lesser-deformed blocks of...
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... the tilt block could not have formed during late Cenozoic extension. We attribute westward tilting to hanging wall rotation along an east dipping normal fault which roots structurally down- ward into the Rongma detachment, but is now buried beneath Quaternary alluvium ( Figure 6a). A minimum slip of $40 km for the Rongma detachment is suggested from the map-view width of footwall metamorphic exposures in the direction of transport (Foldout 2). ...
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... timing and kinematics of these faults are poorly constrained. However, a NE-SW cross section sug- gests that they accommodated minimal shortening ($6 km across the 39-km-long cross section) and exhumation of the metamorphic rocks ( Figure 6b). ...
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... is difficult to precisely constrain the magnitude of slip across several of the major range-bounding normal faults due to the lack of preserved cutoffs. However, a W-E cross section across the $50-km-wide Yibug Caka rift system suggests that a minimum of $2 km of E-W extension is required to produce the observed map relationships (Figure 6a). To both the southwest and northeast beyond the map area, the rift system is kinematically linked with active N70°E striking left-lateral strike-slip faults [Taylor et al., 2003] (Figure 3). ...
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... Our studies suggest that the interior of the central Qiangtang terrane experienced minor denudation since Late Triassic -Early Jurassic exhumation of the CQMB and relatively minor upper-crustal shortening during the Indo- Asian collision (see cross sections in Foldouts 1 and 3; Figure 6b). This implies that the central Tibetan crust may have been significantly thickened by flow or thrusting of crust beneath it. ...
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... However, for most of the suture zones across the Tibetan lithosphere, tectonic models involve the collision of rigid continents with limited intraplate deformation. Notable exceptions include documentation of Mesozoic deformation across Lhasa (Murphy et al., 1997) and Qiangtang (e.g., Kapp et al., 2003aKapp et al., , 2003bKapp et al., , 2005. Part of this issue stems from the protracted and polyphase history of tectonic overprinting and Cenozoic intraconti-nental modification associated with the Himalayan-Tibetan orogen (e.g., Yin et al., 2007;Zuza et al., 2018). ...
Suture zones located across the Tibetan region clearly demarcate the rift-and-drift and continental accretion history of the region. However, the intraplate responses to these marginal plate-tectonic events are rarely quantified. Our understanding of the Paleo-Tethyan orogenic system, which involved ocean opening and closing events to grow the central Asian continent, depends on the tectonic architecture and histories of major late Paleozoic−early Mesozoic orogenic belts. These opening and collision events were associated with coupled intracontinental deformation, which has been difficult to resolve due to subsequent overprinting deformation. The late Paleozoic−early Mesozoic Zongwulong Shan−Qinghai Nanshan belt in northern Tibet separates the Qilian and North Qaidam regions and is composed of Carboniferous−Triassic sedimentary materials and mantle-derived magmatic rocks. The tectonic setting and evolutional history of this belt provide important insight into the paleogeographic and tectonic relationships of the Paleo-Tethyan orogenic system located ∼200 km to the south. In this study, we integrated new and previous geological observations, detailed structural mapping, and zircon U-Pb geochronology data from the Zongwulong Shan−Qinghai Nanshan to document a complete tectonic inversion cycle from intraplate rifting to intracontinental shortening associated with the opening and closing of the Paleo-Tethyan Ocean. Carboniferous−Permian strata in the Zongwulong Shan were deposited in an intracontinental rift basin and sourced from both the north and the south. At the end of the Early−Middle Triassic, foreland molasse strata were deposited in the southern part of the Zongwulong Shan during tectonic inversion in the western part of the tectonic belt following the onset of regional contraction deformation. The Zongwulong Shan−Qinghai Nanshan system has experienced polyphase deformation since the late Paleozoic, including: (1) early Carboniferous intracontinental extension and (2) Early−Middle Triassic tectonic inversion involving reactivation of older normal faults as thrusts and folding of pre- and synrift strata. We interpret that the Zongwulong Shan−Qinghai Nanshan initiated as a Carboniferous−Early Triassic intracontinental rift basin related to the opening of the Paleo-Tethyan Ocean to the south, and it was then inverted during the Early−Middle Triassic closing of the Paleo-Tethyan Ocean. This work emphasizes that pre-Cenozoic intraplate structures related to the opening and closing of ocean basins in the Tethyan realm may be underappreciated across Tibet.
... We synthesized the major subduction and oceanic closure events along the main sutures across Tibet (e.g., the Kunlun, Jinsha, Bangong, and Indus-Yarlung suture zones, from north to south; Figs. 9A and 9B) as shown in Table 2 (e.g., Kapp et al., 2003;Wu et al., 2016;Kapp and DeCelles, 2019;Wan et al., 2019;Liu et al., 2021). We also summarized two oceanic plateau collision events in the Qilian Shan and Qiangtang regions of Tibet (Table 2), which likely behave similarly to microcontinent collision events (e.g., Tetreault and Buiter, 2014). ...
The accretion of future allochthonous terranes (e.g., microcontinents or oceanic plateaus) onto the southern margin of Asia occurred repeatedly during the evolution and closure of the Tethyan oceanic realm, but the specific geodynamic processes of this protracted convergence, successive accretion, and subduction zone initiation remain largely unknown. Here, we use numerical models to better understand the dynamics that govern multiple terrane accretions and the polarity of new subduction zone initiation. Our results show that the sediments surrounding the future terranes and the structural complexity of the overriding plate are important factors that affect accretion of multiple plates and guide subduction polarity. Wide (≥400 km) and buoyant terranes with sediments behind them and fast continental plate motions are favorable for multiple unidirectional subduction zone jumps, which are also referred to as subduction zone transference, and successive terrane-accretion events. The jumping times (∼3−20+ m.y.) are mainly determined by the convergence rates and rheology of the overriding complex plate with preceding terrane collisions, which increase with slower convergence rates and/or a greater number of preceding terrane collisions. Our work provides new insights into the key geodynamic conditions governing multiple subduction zone jumps induced by successive accretion and discusses Tethyan evolution at a macro level. More than 50 m.y. after India-Asia collision, subduction has yet to initiate along the southern Indian plate, which may be the joint result of slower plate convergence and partitioned deformation across southern Asia.
... The evolution of the Paleo-Tethys Ocean in the Tibetan Plateau is a topic of debate, regarding the presence of an in situ ocean in central Qiangtang, as well as the direction of subduction and the timing of the oceanic closure [8][9][10][11][12][13]. The Longmuco-Shuanghu complex in the central Qiangtang of the Tibetan Plateau is generally considered to be a remnant of the Paleo-Tethys Ocean [11][12][13][14]. ...
... The Tibetan Plateau is an amalgamation of terranes that were accreted to the southern margin of Eurasia [10,23]. The interior of the Tibetan Plateau comprises the Kunlun, Songpan-Ganzi, Qiangtang, and Lhasa Terranes from north to south (Figure 1a). ...
... In the central region of the Qiangtang Terrane, a prominent east-west trending complex belt is observed, exposing a series of high-pressure metamorphic rocks and ophiolites [10,16,20] (Figure 1b). These metamorphic rocks primarily comprise garnet phengite schist, marble, eclogite, and blueschist, which were formed via oceanic plate subduction and subsequently exhumed during the Late Triassic period [24][25][26]. ...
The assemblage of oceanic islands and seamounts, arising from the widespread presence of mature oceans, plays a crucial role in reconstructing the evolutionary history of the paleoocean. Oceanic islands or seamounts within the Longmuco-Shuanghu metamorphic complex, a remnant of the Paleo-Tethys Ocean in the central Tibetan Plateau, have seldom been reported due to their remoteness. This study has identified an oceanic island-seamount in the Maoershan area, situated to the west of the Longmuco-Shuanghu metamorphic complex, composed of basalt, diabase, limestone, and siliceous rocks. Based on field observations, petrology, zircon U-Pb dating, whole-rock geochemistry, and Sr-Nd isotopes analyses, we have identified a suite of mafic rocks with OIB affinity. The youngest zircon U-Pb age cluster was concentrated at ~243–241 Ma. The geochemical characteristics of the siliceous rocks indicate a mixture of terrigenous material, suggesting that they formed in a continental margin. In combination with regional geological data, we conclude that the Longmuco-Shuanghu Paleo-Tethys Ocean remained open during the Middle Triassic. Furthermore, a fraction of the oceanic island-seamounts underwent scraping and transformed into a metamorphic complex, while other segments experienced deep subduction, resulting in the formation of high-pressure metamorphic rocks. Collectively, these processes gave rise to the distinctive high-pressure metamorphic complex within the central Qiangtang terrane.
... However, the eastward continuity of this suture is hard to delineate. Kapp et al. (2000Kapp et al. ( , 2003 consider that the Central Qiang- Roger et al. (2010) and Yang et al. (2014). Abbreviations: BH, Bayan Har; CQMB, Central Qiangtang Metamorphic Belt; HK, Hindu Kush; INDO, Indochina; Kh, Kohistan; Lh, Lhasa; NQt, North Qiangtang; P, Pamir; SG, Songpan-Ganze; Sibu, Sibumasu; SQt, South Qiangtang; and WB, West Burma. ...
... From the Yushu to Litang regions, rocks older than 227 Ma are indeed affected by an early phase of deformation characterized by top-N asymmetrical, steeply plunging fabrics, which may relate to this subduction event (Yang et al., 2014). Metamorphic rocks from the central Qiangtang terrane indicate peak eclogitic conditions at c. 244-230 Ma (Dan et al., 2018;Pullen et al., 2008) and exhumation at c. 214-207 Ma (Dan et al., 2018;Kapp et al., 2003;Q.-G. Zhai et al., 2011), that can be ascribed to this subduction. ...
The Tibetan Plateau was formed by intense Cenozoic shortening (up to 1,100 km) of a composite “proto‐Tibet,” itself the product of a long Paleozoic and Mesozoic history of accretion of Gondwana‐derived continental fragments and volcanic arcs against the Asian continental margin. The difficult access and the scarcity of outcrops have long limited the possibilities of studying these Mesozoic suture zones in the heart of the Plateau. In this work, we present new U‐Pb and ⁴⁰Ar/³⁹Ar ages from the highly deformed units of the Yushu mélange, along the Jinsha Suture in the northeastern Qiangtang terrane. Early Triassic (c. 253 Ma) to Middle Jurassic ages (c. 165 Ma) complement the existing data set and help to refine the chronology of the Paleo‐Tethyan oceanic subductions which have structured the northeastern part of the Qiangtang terrane. The Yushu mélange records at least three successive tectono‐magmatic events. The opening of a back‐arc basin during the northward Paleo‐Tethyan subduction along the Longmu Co‐Shuanghu Suture during Early to Middle Triassic; then its closure during the southward subduction of the Songpan‐Ganze Ocean along the Jinsha Suture in Late Triassic. Finally, a shortening phase related to the continental collision of the Songpan‐Ganze and Qiangtang blocks from Late Triassic to Early‐Middle Jurassic. No evidence for any high‐ or mid‐temperature Cenozoic reactivation of the Jinsha suture in our study area is recorded.
... The substantial extension in the upper plate would in turn favor the exhumation of (U)HP metamorphic rocks ). Additionally, a variety of orogenic P-T paths that have been reported from many collisional orogens, such as central Tibet (Kapp et al., 2003), Alps (Kurz et al., 1998), Himalayas (Wilke et al., 2010), and southern Altyn (Dong and Wei, 2021), show similar twostep exhumation history delimited by a phase of LP near-isobaric heating, which suggest that exhumation driven by slab rollback appears to be a fundamental mechanism behind (U)HP metamorphic rock exhumation within collisional orogens. ...
Exhumed (ultra)high-pressure ([U]HP) metamorphic rocks are markers of paleo-subduction zones and can provide crucial implications for the geodynamic evolution of subduction-exhumation. A variety of (U)HP metamorphic rocks from many collisional orogens have commonly documented a low-pressure high-temperature overprint, which appears to indicate a pervasive geodynamic process behind (U)HP metamorphic rock exhumation. A good case study of garnet amphibolite and associated garnet-biotite gneiss with an unambiguous low-pressure high-temperature overprint in the Xixia-Xiaguan area of the North Qinling Orogen, central China, provides a significant opportunity to uncover this geodynamic process. A detailed study of petrography, mineral chemistry, and phase equilibria modeling suggests that the investigated garnet amphibolite and garnet-biotite gneiss have jointly experienced multistage exhumation processes with near-isothermal decompression from the (U)HP eclogite facies (26.8−29.0 kbar/740−775 °C) to the medium-pressure (MP) amphibolite facies (8.7−10.0 kbar/740−775 °C), subsequent remarkable near-isobaric heating to the low-pressure (LP) granulite facies (6.8−8.2 kbar/832−835 °C), followed by final decompression and cooling to the LP amphibolite facies (5.8−6.8 kbar/740−757 °C). U-Pb age dating of zircons from the garnet amphibolite and garnet-biotite gneiss yielded metamorphic ages of ca. 500 Ma, 450 Ma, and 400 Ma, which we consider to represent (U)HP eclogite-facies, LP granulite-facies, and late LP amphibolite-facies metamorphism, respectively. According to the regional geology and the metamorphic history we have determined, this multistage exhumation process of two-step exhumation stages delimited by a phase of LP near-isobaric heating was associated with slab rollback. Accordingly, we propose a tectonic model of exhumation driven by slab rollback for the geodynamic evolution of (U)HP metamorphic rock exhumation in the North Qinling Orogen. Additionally, a combination of previous studies and our new results suggests that exhumation driven by slab rollback appears to be a fundamental mechanism for the (U)HP metamorphic rock exhumation within collisional orogens.
... Since the late Early Cretaceous (ca. 125 Ma), the LSTB records episodic SE-ward thrusting, which is probably related to the eastward extrusion of the Songpan-Ganze Terrane that is probably due to the collision between the Lhasa and Qiangtang terranes during the Cretaceous and the collision between the Indian and Eurasian plates during the Cenozoic (Kapp et al., 2003;Volkmer et al., 2007;Xue et al., 2017;Yin & Harrison, 2000). The entire LSTB underwent strong D 3 LPS during NW-SE shortening, which gave rise to a basin-ward progression from oblate weak cleavage fabrics to prolate pencil structure fabrics and then to moderately oblate incipient deformational fabrics with NE-SW magnetic lineations. ...
Reconstructing the deformation sequence and strain history of the Longmen Shan thrust belt (LSTB) has significant implications for the growths of the SW Qinling orogenic belt and the Tibetan Plateau. However, the Mesozoic–Cenozoic propagation of the LSTB remains poorly understood owing to weak constraints on strain variations. We conducted a comprehensive structural investigation and made measurements of anisotropy of magnetic susceptibility along the entire LSTB. Magnetic fabrics are represented by prevalent layer‐parallel shortening (LPS) fabrics, intersection lineation fabrics, and folding fabrics with magnetic lineations trending NE–SW, WSW–ENE, NW–SE, and N–S, corresponding to four compressional deformations. AMS results and structural analyses, revealed four phases of deformation (D1, D2, D3, and D4) that were characterized respectively by top‐to‐the‐SSE thrusting in the northern LSTB at >219–164 Ma, top‐to‐the‐SW thrusting in the central‐northern LSTB at >201–164 Ma, top‐to‐the‐SE thrusting of the LSTB at 125–5 Ma, and top‐to‐the‐east thrusting at 5–0 Ma in the LSTB. D1, D3, and D4 LPS fabrics exhibit a strain evolution that progressed from incipient deformation to pencil structure to cleavage fabrics, corresponding to moderately oblate, prolate, and oblate strain ellipsoids, respectively. The intersection lineation fabrics imply a hinterland‐ward progression from LPS fabrics to cleavage‐controlled fabrics and non‐coaxial superimposition of D2 on D1. Therefore, the early Mesozoic LSTB developed owing to the superimposition of D2 on D1 being non‐coaxial, likely suggesting southward growth of the SW Qinling orogenic belt, whereas the modern LSTB was formed by the superimposition of D4 on D3, implying non‐coaxial eastward growth of the Tibetan Plateau.
... The Qinghai-Tibetan Plateau consists of a collage of blocks divided by major fault zones or suture zones. These suture zones, from south to north, include the Yarlung Zangbo, the Bangong-Nujiang, and Longmu Co-Shuanghu suture zones, and have been regarded as representing closure of paleooceans (Yin and Harrison, 2000;Kapp et al., 2003;Gehrels et al., 2011;Pan et al., 2012;Wu et al., 2020). The Paleo-Tethys Ocean lies between the Eurasia and Gondwana continents. ...
The Permian Period was a critical time interval during which various blocks of the Qinghai-Tibetan Plateau have experienced profound and complex paleogeographical changes. The supercontinent Pangea was formed to its maximum during this interval, hampering a global east-to-west trending equatorial warm ocean current. Meanwhile, a semi-closed Tethys Ocean warm pool formed an eastward-opening oceanic embayment of Pangea, and became an engine fostering the evolutions of organisms and environmental changes during the Paleozoic-Mesozoic transition. Stratigraphy and preserved fossil groups have proved extremely useful in understanding such changes and the evolutionary histories of the Qinghai-Tibetan Plateau. Widely distributed Permian deposits and fossils from various blocks of the Qinghai-Tibetan Plateau exhibited varied characteristics, reflecting these blocks’ different paleolatitude settings and drifting histories. The Himalaya Tethys Zone south to the Yarlung Zangbo suture zone, located in the northern Gondwanan margin, yields fossil assemblages characterized by cold-water organisms throughout the Permian, and was affliated to those of the Gondwanaland. Most of the exotic limestone blocks within the Yarlung Zangbo suture zone are Guadalupian (Middle Permian) to Early Triassic in age. These exotic limestone blocks bear fossil assemblages that have transitional affinities between the warm Tethys and cold Gondwanan regions, suggesting that they most probably represent seamount deposits in the Neo-Tethys Ocean. During the Asselian to Sakmarian (Cisuralian, also Early Permian), the Cimmerian microcontinents in the northern part of Gondwana preserved glacio-marine deposits of Asselian to Sakmarian, and contained typical Gondwana-type cold-water faunas. By the middle Cisuralian (∼290–280 Ma), the Cimmerian microcontinents rifted off from the Gondwanaland, and drifted northward allometrically due to the active magmatism of the Panjal Traps in the northern margin of the Indian Plate. Two slices of microcontinents are discerned as a result of such allometic drifting. The northern Cimmerian microcontinent slice, consisting of South Qiangtang, Baoshan, and Sibuma blocks, drifted relatively quickly, and preserved widespread carbonate deposits and warm-water faunas since Artinskian. By contrast, the southern Cimmerian microcontinent slice, consisting of Lhasa, Tengchong, and Irrawaddy blocks, drifted relatively slowly, and were characterized by widespread carbonate deposits containing warm-water faunas of late Kungurian to Lopingian (Late Permian). As such, these blocks rifted off from the northern Gondwanan margin since at least the Kungurian. Thus, it can be inferred that these blocks were incorperated into the low latitude, warm-water regions later than the northern Cimmerian slice. Such discrepancies in depositional sequences and paleobiogeography imply that the rifting of Cimmerian microcontinents resulted in the formation of both Meso-Tethys and Neo-Tethys oceans during the Cisuralian. By contrast, the North Qiangtang block, because of its further northern paleogeographical position, contains warm-water faunas throughout the whole Permian Period that are affiliated well with the faunas from the South China, Simao, and Indochina blocks. Together, these blocks belonged to the members of the northern Paleo-Tethys Ocean. Thus, an archipelagic paleogeographical framework divided by Paleo-, Meso-, and Neo-Tethys oceans was formed, fostering a global biodiversity centre within the Tethys warm pool. Since most of the allochthonous blocks assembling the Qinghai-Tibetan Plateau were situated in the middle to high latitude regions during the Permian, they preserved most sensitive paleoclimate records of the Late Paleozoic Ice Age (LPIA), the Artinskian global warming event, and the rapid warming event at the end-Permian. Therefore, sedimentological and paleontological records of these blocks are the unique window through which we can understand global evolutions of tectonic movement and paleoclimate, and their impacts on spatiotemporal distributions of comtemporaneous biotas.
... These were accompanied and corroborated by, numerous studies that he, his students and colleagues conducted in key places such as the Qinling-Dabie, Gangdese, Himalaya, Karakoram, central and northern Tibetan plateau, Altyn Tagh, Pamir, Tarim, Tian Shan, and northeastern India. These studies have remarkably shaped our views on many critical issues, among which are the north-south trending rift system of southern Tibet (Yin A, 2000), the southern extent of the Karakoram fault (Murphy et al., 2002), the blueschist-bearing Qiangtang metamorphic belt (Kapp et al., 2003), the structural relationship between the Main Central Thrust and the South Tibetan Detachment System in the High Himalayas (Webb et al., 2007), the conjugate strike-slip fault system in central Tibet (Yin A and Taylor, 2011), and a possible seismic gap in North China (Yin A et al., 2015). At the same time, An Yin even managed to develop a new model for on-going deep (15−50 km) slow-slip events (Yin A et al., 2018a) and tectonic tremor (Yin A, 2018b) and to establish the plate convergence processes at ca. 2.0 Ga (Yin A et al., 2020). ...
... This metamorphic belt is exposed over an east-west trend of approximately 600 km and a north-south extension of approximately 150 km . This zone is comprised of low-temperature and high-pressure metamorphic eclogite-blueschist rocks, ophiolitic mélange, metasedimentary rocks, ocean-island basalt (OIB)-type basalts, and arc magmatic rocks (e.g., Li et al., 1997;Kapp et al., 2000Kapp et al., , 2003Zhai et al., 2010;Jiang et al., 2015). Although much work has been conducted on the ophiolitic mélange, high-pressure metamorphic rocks, and magmatic rocks, underthrusting and in-situ suture zone models of their dynamic formation remain controversial (e.g., Pullen et al., 2011;Liang et al., 2020). ...
... Comprehensive studies on the structure, metamorphism, and exhumation process have contributed to raise the model that underthrust mélange from the Jinshajiang suture zone moved 200 km southward to upper crustal level via Late Triassic-Early Jurassic normal faulting and exhumated as a blueschist-bearing metamorphic belt within the central part of an integral Qiangtang terrane (Kapp et al., 2000(Kapp et al., , 2003Pullen et al., 2011). Alternatively, the metamorphic belt may represent the remnants of an ancient ocean between the northern and southern Qiangtang blocks based on contrasting magnetotelluric properties, biotas, and depositional settings. ...
... Some previous studies have suggested that the CQMB originated from the Jinshajiang suture zone in the north of the Qiangtang Basin (Kapp et al., 2003;Pullen et al., 2008). If this is the case, radiolarian faunas in both the Jinshajiang suture zone and the CQMB should be contemporaneous. ...
The paleogeographic position of the North Qiangtang Block, as well as the origin of the Central Qiangtang Metamorphic Belt (CQMB) have subjected to considerable debate that hampers the understanding of the early evolution of the Paleo-Tethys Ocean. This study reports a new radiolarian fauna of a Famennian age (Late Devonian) from the ophiolitic mélange south of Gangtang Co, northern Tibet, including Callela par-vispinosa Won, Entactinia foveolata Nazarov, and Plenoentactinia pinguis Won. The discovery of Devonian radiolarians in the CQMB strongly supports the model that the Longmu Co-Shuanghu suture zone represents the main branch of the Paleo-Tethys Ocean. A correlation of the Late Devonian radiolarian in Tethys realm reveals that the Longmu Co-Shuanghu suture zone was connected to the Changning-Menglian suture zone in western Yunnan, the Chiang Mai-Inthanon and Chanthaburi suture zones in Thailand, and the Bentong-Raub suture zone in Malay Peninsula. The synchronous advent of Late Devonian radi-olarians suggests that the Paleo-Tethys Ocean may have opened during that time. Ó
... Tectonically, the Qiangtang Basin is characterized by one Central Uplift sandwiched by two depressions (Northern Qiangtang Depression and Southern Qiangtang Depression) (Fig. 1b) (Zhao et al. 2001;Wang et al. 2004). The Paleo-Tethys Ocean is thought to have formed in the early Carboniferous, shrunk during the Permian to the Late Triassic, along the Hoh Xil-Jinshajiang suture zone due to collision orogenesis (Dewey et al. 1988;Pearce and Mei 1988;Kapp et al. 2003 ). The existence of the Bangong Lake-Nujiang suture zone suggests that the Meso-Tethys Ocean lied between the Lhasa and Qiangtang terranes during the Late Triassic-Early Jurassic time (Yin and Harrison 2000;Tang and Wang 1984;Pearce and Mei 1988). ...
... During the Middle-Late Triassic, the Paleo-Tethys Ocean was subducted southward under the Qiangtang Basin (Dewey et al. 1988;Kapp et al. 2003;Ye et al. 2008). ...
... During this interval, the Qiangtang Basin was uplifted by the collision, which caused a rapid sea level regression from north to south (Kapp et al. 2003). Thus, the northern ...
The end-Triassic mass extinction (ETME) is one of the five catastrophic extinction events. However, the driving mechanisms of biodiversity loss during this interval remain controversial. In this study, we investigate the marine sediment geochemistry and fauna across the Triassic-Jurassic boundary in the Wenquan section of Qiangtang Basin, and the triggering mechanism of the Late Triassic extinction in the eastern Tethys Ocean. Our study shows that the main pulse of the ETME occurred in Bed 8, manifesting as the disappearance of four brachiopod species, a significant decrease of other faunas, and the “Lilliput Effect” on bivalves. Analyses of pyrite framboids and redox-sensitive trace elements, suggest the development of photic zone anoxia near the T/J boundary and coincident with the Late Triassic extinction. Thus, the development of abrupt and intense photic-zone anoxia could play an important role in the end-Triassic extinction.
Supplementary material: https://doi.org/10.6084/m9.figshare.c.6771606
